1. Field of the Invention
The invention relates to a dispersion plate that is provided in an exhaust pipe of an internal combustion engine to disperse an exhaust flow and an internal combustion engine including the dispersion plate in the exhaust pipe.
2. Description of Related Art
An oxygen concentration sensor for detecting oxygen concentration in exhaust gas is provided in an exhaust pipe of an internal combustion engine, and the oxygen concentration in the exhaust gas serves as an index value of an air-fuel ratio of air-fuel mixture. In operation control of the internal combustion engine, an intake air amount or a fuel injection amount is adjusted in accordance with a detected value by the oxygen concentration sensor, and the air-fuel ratio of the air-fuel mixture is thereby controlled.
In addition, it has been suggested to provide a dispersion plate that disperses an exhaust flow in a portion on an exhaust upstream side of the oxygen concentration sensor in the exhaust pipe (for example, see Japanese Utility Model Application Publication No. 6-73320 (JP 6-73320 U)). This dispersion plate has a deflection plate that deflects the exhaust flow. This deflection plate extends in an inclined direction and a twisted direction with respect to an extending direction of the exhaust pipe. A swirl flow (in detail, a flow that swirls in a spiral shape in the extending direction of the exhaust pipe) is formed on the inside of the exhaust pipe by the above deflection plate. This swirl flow agitates the exhaust gas, so as to suppress fluctuation of the oxygen concentration in the exhaust gas in the exhaust pipe. Thus, detection accuracy of the oxygen concentration in the exhaust gas by the oxygen concentration sensor is increased.